CCE Lighting & Material Interactions 2 — Questions and Answers
Question 1: A fabric appears vibrant under tungsten lighting but dull under fluorescent. This phenomenon is best described as:
- Simultaneous contrast
- Metamerism (Correct answer)
- Chromatic adaptation
- Color constancy failure
Correct answer: Metamerism
Metamerism occurs when two colors match under one light source but differ under another due to different spectral reflectance curves.
Question 2: Which material finish would show the greatest variation in apparent color when viewed at different angles?
- Matte latex paint
- Flat chalk paint
- Pearlescent automotive finish (Correct answer)
- Eggshell wall paint
Correct answer: Pearlescent automotive finish
Pearlescent finishes contain mica or interference pigments that shift color with viewing angle due to thin-film interference effects.
Question 3: The Color Rendering Index (CRI) measures a light source's ability to:
- Produce the full visible spectrum
- Accurately render object colors compared to a reference illuminant (Correct answer)
- Minimize glare on reflective surfaces
- Maintain consistent color temperature over time
Correct answer: Accurately render object colors compared to a reference illuminant
CRI compares how faithfully a light source renders 8 standard test color samples relative to a reference illuminant of the same color temperature.
Question 4: A north-facing room receives predominantly which type of daylight, and how does it affect color perception?
- Warm yellow light that enriches reds and oranges
- Cool blue-shifted light that enhances blues and grays (Correct answer)
- Neutral white light with balanced color rendering
- Infrared-rich light that distorts warm hues
Correct answer: Cool blue-shifted light that enhances blues and grays
North-facing rooms receive indirect, blue-shifted skylight (higher CCT) that tends to make colors appear cooler and slightly desaturated in warmer hues.
Question 5: Velvet fabric often appears darker than other textiles of the same dye lot. The primary reason is:
- Velvet absorbs more dye during processing
- The pile structure causes multiple internal light reflections that trap light (Correct answer)
- Velvet fibers have a lower refractive index
- Velvet is inherently more saturated in hue
Correct answer: The pile structure causes multiple internal light reflections that trap light
The upright pile of velvet causes light to bounce repeatedly within the fiber structure, increasing absorption and producing a deeper, darker apparent color.
Question 6: When specifying paint colors for a room that will be lit with LEDs rated at CRI 80 vs. CRI 95, the main practical concern for a color expert is:
- The higher CRI bulb will make all colors appear brighter
- Low CRI sources may render certain hues inaccurately, making sample selection under those conditions misleading (Correct answer)
- CRI differences only affect blue and green hues
- CRI 80 bulbs will cause paint to fade faster
Correct answer: Low CRI sources may render certain hues inaccurately, making sample selection under those conditions misleading
A CRI 80 source may render reds and magentas poorly, so colors selected under it may look different under the CRI 95 source the client may later purchase.
Question 7: Optical brightening agents (OBAs) in white paper or fabric absorb UV radiation and emit visible blue light. Their primary visual effect is to:
- Make the surface appear warmer and creamier
- Increase apparent whiteness and brightness under UV-containing light sources (Correct answer)
- Improve the material's CRI
- Shift the hue of printed colors toward green
Correct answer: Increase apparent whiteness and brightness under UV-containing light sources
OBAs fluoresce blue-white under UV light, adding luminance to the surface and making whites appear brighter and cooler than they would otherwise.
CCE Lighting & Material Interactions 2
A fabric appears vibrant under tungsten lighting but dull under fluorescent.
This phenomenon is best described as: